Method and apparatus for manufacture of seamless metallic tubes



Aug. 26, 1930.

T. H. NELSON METHOD AND APPARATUS FOR MANUFACTURE oF sEAMLEss METALLIC TUBES Filed March 13, 1929 Patented Aug. 26, 1930 TES PATENT Price TOM H. NELSON, OF VILLA NOVA, PENNSYLVANIA Application tiled March 13, 1929. Serial No. 346,564.

The present invention relates broadly to metallurgy and more especially to the manufacture of metallic articles such as, for eX- ample, seamless tubes.

Hereinafter in the specification the invention is described more particularly with reference to the application thereof to steel billets, but, except where the description and claims are limited specifically to steel, it is lo understood that the invention may be carried out with metals other than. ferrous metals and their alloys.

The present improvement in the art relates to methods and devices for assisting the action of the work faces of hot metal working devices during the work cycle, and the present disclosure of the invention is with reference to the use thereof in the piercing of hot billets in manufacturing seamless tubes from solid metallic billets.

Heretofore in the art of making seamless steel tubes it has been customary to provide a solid hard metal piercing head adapted to enter a steel billet which is forced against 25 and over the piercing head by feeding rolls in such manner that the billet is moved in the direction of its axis over the head, whereby the head converts the hot steel billet into a hollow seamless tube. It was believed the o harder the point the more effect-ive the head,

and in some cases even diamond points have been tried. Observation of the piercing operation shows that the work face of the piercing head is subjected to very substantial stresses and that this surface of the head is often seized by the hot steel billet, resulting in both the head and the tube being deeply scarred and torn. ltwas not unusual in the prior art methods for heads to stick in the 40 billets by being welded thereto. This resulted in either tearing` the inner surface of the tube or causing the head to become so 'lirmly embedded in the billet that the billet was spoiled and could not be pierced. These i5 diflicultics are particularly prevalent with billets of chromium and nickel chromium steel alloys of the stainless steel type.

The present invention overcomes the difficulties of the known prior art in that by the use ot' the present invention it has been found hard wood, such as oak set in the nose of the head produces excellent results. It is found that the piercing operation may be performed with `less power when the present invention is used and that the 'interior of the tube formed by such a piercing head is smooth and not roughened, as was the case in the use of the prior art methods, and furthermore, the novel piercing head when passed through a steel billet is found not to show evidence of abuse or severe wear, which is so noticeable in the use of heads of the prior art. l

It is recognized that the present inventions may be practiced by immaterial departures from the disclosures herewith and therefore .the disclosures in these specifications and drawingsare to be understood as illustrative and not in the limiting sense.

Other and further objects of the present invention will in part be obvious and will in part be pointed out hereinafter in the written specification by reference to the accompanying drawings, forming a part thereof. Like characters are used to designate like parts throughout the several figures of the drawings.

Fig. l is a View showing, more or less diagrammatically, a billet being forced by feed rolls over a piercing head comprising the preferred form of the present invention, and showing a portion of the pierced billet in section.

Fig. 2 is a view illustrating a common form of piercing head equipped with a wooden plug in accordance with the present invention, and showing the nose of the head in section.

Fig. 3 is a cross section through a portion of a pierced steel billet made in accordance with thc inventions herein described and claimed, and diagrammatically illustrates the effect-produced by these novel methods onthe direction of the steel crystals when the billet has been pierced. according to the present invention.

Referring now more especially to Fig. 1 of the drawings, which illustrates a pair of feed rolls 1 and 2, driven by any suitable mechanism well known in the art, set in such manner as to feed a hot billet 4 over a piercing head 5 which is supported on a stem or shaft 6 to receive the forces exerted by the feed of the hot billet 4 over the head 5. The features described to this point are well known in the art and for that reason more specific description and illustrationis unnecessary. i

The present invention, as applied to this Well known mechanism, speciicallyresides in the provision of lubricating means, for eX- ample, a wooden plug 7 set in the nose of the piercing head 5, as illustrated in Fig. 2. In practice a hard wood plug, for example, an oak plug W8 -to 1/2 of an inch'in diameter, having a length of to one inch, inserted in the nose of the head, Works very satisfactoril in piercing hot billets of chrome and nick l steel alloys of the stainless variety, whi are the most diHcult billets to pierce. By th of the present invention, the werk face of the piercing head is not roughened but remains substantially smooth and free from scar marks, and the interior of the seamless tube is bright and smooth.

Fie'. 3 illustrates a section of a steel tube' whic showsl the action of the novel piercing head on the metal being pierced. The novel piercing head 5 pierces the billet without the head seizing the hot metal, or tearing or dragging the metal, as is the action of piercing heads of the known prior art. This appears to cause the metal to flow in the direc-4 tion of axes of the metal crystals without serious rupture or actual breaking up of the crystal structure. The result is a better and much stronger tube than is produced by the prior art methods. Y

.The foregoing description of the use ofthe lnvention to the piercing of hot steel billets to form seamless tubes is based uponl actual experience. It appears that during the progress of the piercing head through the billet that the wooden plug seems t0 be destroyed and is probably consumed and gasitled. It seems-probable that-these gases of combustion are highly compressed in front ot the piercin head and vassist in opening up the metal bers or crystals in advance of the head, and that a portion of these gases, to-

gether with the more solid particles of combuston such as carbon, etc., ilow back over the work face of the head during the piercing operation and act as lubricants or a protecting coating for the work face. Itchas been observed that when the piercing head breaks through the end of the billet that there is a slight explosion similar to the sudden release of a highly compressed gas. This seems to clearly indicate that a portion of the gas is retained in a pocket formed in the billet ahead of the piercing tool.

Tubes formed by the use of the present invention are readily distinguishable from tubes formed by prior art methods, in thit the interior ofthe tubes formed by the present method are smooth and' bright, whereas the tubes formed by prior art methods have rough and often have torn interior side walls with projections and cracks which cannot be entirely eliminated bya subsequent working. Another result due to the crystals A in the steeel being left with their axes parallel to the aXis of the tube greatly increases strength in kthe finished tube. It is genrally rcognized by metallurgists that the greatest' strength of a piece of steel is where the stress is applied transversely to the length of the steel crystals. A steel tube made by they use of this inventionhaving the crystals parallel to the axis of the tube has greater resisting powers to internal or external stresses tending to burst or collapse the tube than does a steel tube made by the prior art methods. Where the columnar crystals were broken upy or torn apart-and were left with their axes more or less heterogeneously arranged due to the seizing and tearing of the metal on t-he piercing head.

While the present invention has been disclosed more especially with reference to the manufacture of seamless steel tubes, the invention has a broader aspect in that i't relates to the prevention of the seizing of hot metal forced over any forming tool and it may be applied todrawing or pressing or extruding metals whereby the work faces of the dies or mandrels or heads are subjected to an enclosed gas or lubricating material supplied during the work cycles of the devices The terms hot billet and hot metal used in the specification and claims are intended to refer to billets or metal which are heated t6` several hundred degrees, i. e., slightly less than Welding temperature of the metal. In other words, these terms mean such temperatures as are ordinarily used in the art for hot working of the metal to form various articles by metal flow while the metal is in a somewhat plastic condition.

What I claim is:

l. The method of making seamless tubes comprising supporting a piercing head, forcing a hot metal billet over said piercing head and providing pocketed combustible material adjacent the nose of said piercing head wherebysaid combustible material is burned under pressure during the piercing operaV tion.

2. The method of making seamless tubes comprising causing a relative movement between a hot metal billet and a piercing member, and providing a pocketed material producing highly compressed gases in front of said piercing member during the piercing operation.

3. The method of making seamless tubes comprising causing a relative movement between a hot metal billet and a piercing member and carrying a supply of material'containing carbon by the nose of the piercing member to produce pressure in front of the piercing member during the piercing operation.

4. Themethod of making seamless tubes comprising causing a relative movement between a piercing member and a hot metal billet and providing wooden fuel adjacent the nose of said member whereby said wooden fuel is consumed during'the piercing operation. 7

5. In a device for making seamless tubes, the combination of means to cause a relative movement between a piercing member and a hot metallic billet, and a chamber carrying a supply of combustible material adjacent the nose of said piercing member and adapted to be consumed during the piercing opn eration, said chamberbeing open only toward the front' of said member.

6. A device for manufacture of seamless tubing comprising a piercing member, means to cause a relative movement between said piercing member and a hot metal billet, said piercing member being provided with an opening adjacent the nose of the member, and Wooden material mounted in said opening whereby said material is consumed during the piercing operation to :form hot compressed gases forward of said piercing member.

7 A device for making seamless tubes comprising a piercing head provided with an opening in the nose thereof, a wooden plug mounted in said opening, and means to cause a relative longitudinal axial movement between a hot metalbillet and said piercingy head whereby said head is driven lengthwise of said billet to transform the same into a seamless tubular member. i

8. In a device for making seamless tubes, the combination of al piercing member having an opening in the nose thereof, a plug of hard wood mounted in said opening, and feeding means to feed a hot metallic billet over said piercing member in an axial longitudinal direction whereby said piercing member pierces said billet to form a seamless tubular article.

9. In the art of working hot metal, a Jforming member adapted to operate upon a mass of heated metal, means to cause a relative movement between said member and said heated metal,and means comprising a chamber open only at the front of said member providing combustible material adapted to be consumed by said hot metal and to cause the products of combustion from said material to flow over the` work face of said member during the work cycle of said member.

10. The method of working hot masses of metal comprising providing a shaping member, causing relative movement between 'the work, face of said member and said metal, and supplying a fluidcomprising the combustion product of burning wood between said work face and said hot metaldurng the work cycle of said member.

11. The method of working hot masses of metal comprising providing a shaping member, causing relative movement between the work face of said member and said metal, and supplying a predetermined amount of carboniferous material between said work face and said hot metal during the work cycle.

of said member, while supporting said material by a solid closed walled chamber open only at .the front.

12. The method of working hot masses of metal comprising providing a shaping member, causing relative movement between the work face of said member and said metal, and supplying from a chamber open only at the work face of said member carboniferous fluid material under pressure between said work face and said hot metal during the work cycle of said member.

TOM H. NELSON. 

